I'm a male, but I don't really think that makes a difference. "Guys and girls" is how I grew up. For me, it's the same as "men and women" and "blokes and ladies". Personally, I don't think calling females "girls" is a bad thing. I assume you feel the term "girl" implies they lack maturity or something along those lines? Do you think "ladies" is better than 'girls'?
May I pose a question? If a group of males were in the way of where you needed to be, say for instance they were sitting down and you were standing, what term would you use when getting their attention? For example: 'Excuse me _____ but could I...' Which word would you use to fill in the gap?